PHP 4.0 was released in 2000 and it's core was rewritten and named ___________________.

Zend Engine

What version of PHP are we working with in 2016?

PHP version 7.0 (7.0.1 released 12/15)

Version 6.0 was skipped because there was issues with Unicode so instead of releasing version 6.0, the Unicode functionality of Version 6.0 was added to a minor release of 5.0 and Version 6.0 was skipped entirely.

The closing PHP tag is only needed if the script is going to contain HTML.

T/F: PHP is a weakly typed language meaning that we do not have to declare a variable type before declaring a variable.

A) True
B) False

A) True

In PHP you do not have to declare a type in order to declare a variable. Both of the following examples are correct;

$message="Hello World!";

$message="12.5";

The shorthand version for printing out a variable inside HTML code is;

A) <php echo $message>B) <?=$message?>
C) <?$message?>

B) <?=$message?>

<?=$message?> is the same as <?php echo $message ?>

(this multiple choice question has been scrambled)

What is the difference between string builder and string buffer?

String is an immutable object which means the value cannot be changed where as StringBuffer is mutable. The StringBuffer is Synchronized hence thread safe where as StringBuilder is not and suitable for only single threaded instances.

PHP is a server side scripting language commonly used for web applications. PHP has many frameworks and CMS for creating websites. Even a non-technical person can create sites using its CMS. WordPress, osCommerce are the famous CMS of php. It is also an object oriented programming language like java, C-sharp etc. It is very easy to learn.

What is the use of "echo" in PHP?

It is used to print data in the webpage,

Example: <?php echo 'Car insurance'; ?>

echo and print are very similar commands however it is important to know that the print statement is a little slower in execution than the echo command.

Echo has no return value while print has a return value of 1 so it can be used in expressions.

Echo can take multiple parameters (though little used) while print can take one argument.

What methods are available to include a file on a PHP page?

We can include a file using "include() " or "require()" function with file path as its parameter.

What's the difference between include and require?

If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

What is the difference between the following methods; require_once(), require(), include()?

require() includes and evaluates a specific file, while require_once() does that only if it has not been included before (on the same page). So, require_once() is recommended to use when you want to include a file where you have a lot of functions for example. This way you make sure you don't include the file more times and you will not get the "function re-declared" error.

What are the differences between the GET and POST methods ?

We can send 1024 bytes using GET method but POST method can transfer large amount of data and POST is the secure method than GET method.

How can you declare an array in PHP?

Eg : var $arr = array('apple', 'grape', 'lemon');

What is the use of 'print' in PHP?

This is not actually a real function, It is a language construct. So you can use it without parentheses with its argument list. The print function outputs to the screen like the echo() function however it is slightly slower in performance.

Example print('PHP Interview questions'); print ('Job Interview ');

What is the purpose of the function in_array() in PHP?

in_array is used to check whether a value exists in an array.

Example: Search for the value "Glenn" in an array and output some text;

<?php

$people=array("Peter", "Joe", "Glenn", "Robert");

if (in_array("Glenn", $people))

{echo "Match Found";

}

else

{echo "Match Not Found";

}

?>

What is the use of count() function in PHP?

count() is used to count all elements in an array, or something in an object.

Example: Return the number of elements in an array

<?php

echo count($people);

?>

Returns the number of people in the array list.

What’s the difference between include and require?

It’s how they handle failures. If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

What is the difference between Session and Cookie?

The main difference between sessions and cookies is that sessions are stored on the server, and cookies are stored on the user’s computers in the text file format. Cookies cannot hold multiple variables, But Session can hold multiple variables. We can set expiration for a cookie, The session only remains active as long as the browser is open. Users do not have access to the data you stored in Session, Since it is stored in the server. Session is mainly used for login/logout purpose while cookies are used for user activity tracking.

Each of the array elements is a substring of string formed by splitting it on boundaries formed by the string delimiter.

Name some PHP frameworks;

Laravel - Laravel is a PHP web application framework with expressive, elegant syntax, aiming to take the pain out of web development by easing common tasks, such as authentication, routing, sessions and caching.

CodeIgniter - CodeIgniter is a powerful PHP framework with a small footprint, built for those who required a simple, yet elegant toolkit to build fully-featured web applications. It requires nearly zero configuration, with no restrictive coding rules, and offers simple solutions to complex application requirements.

CakePHP - CakePHP enables you to build web applications faster, using code generation features to rapidly build prototypes. There is no complicated configuration, just setup your database and you're ready to go. Translations, database access, caching, validation, authentication and more are all built into the framework. It comes packaged with clean MVC conventions, to guide you in developing your application. CakePHP can handle every aspect of your application, from the user's initial request all the way to the final rendering of a web page. The framework provides a basic organizational structure, from filenames to database table names, to keep your entire application consistent and logical. CakePHP also comes with built-in tools for validation and protection against SQL injection, form tampering and more, to help keep your application safe and secure.

Symfony - Symfony is a PHP framework to speed up the creation and maintenance of your web applications. By using existing 'de facto' standards of PHP, such as PHPUnit, and naming conventions for classes, you're not confined within the Symfony environment, but instead have the freedom to choose the software components that you want to use. It provides a set of prefabricated components that can be rapidly integrated into your application, combined with a clear methodology to help you work both efficiently and effectively on the most complex tasks. The use of Best Practices guarantees the stability, maintainability and upgradeability of any application you develop. You can choose the Full Stack (complete) version if you want to develop a complex application, or Brick by Brick, to build your own framework according to the functionality you need, or Microframework, as a standalones used to develop specific functionality in your project.

Zend Frmework 2 - Zend Framework 2 is an open-source framework for developing web applications, using object-oriented code. The components in the standard library form a powerful an extensible framework when combined, offering a robust, high performance MVC implementation. It's easily extensible, adapting to your needs, with a modular base so you can use building blocks in combination with other applications or frameworks. Using the ZendService you can implement client libraries to access the most popular web services available. As Zend is a collection of classes, you can just load the components you need, to take advantage of the components as individual libraries, instead of the framework as a whole, cutting down on unnecessary project bloat. With no model implementation you are free to implement the framework and components in whatever way you need, free of predefined restraints.

Phalcon - Phalcon is a PHP 5 framework that is implemented as a C extension to offer lower resource consumption and high performance. There's no need to learn or use the C Language, as the functionality is exposed as PHP classes ready to use. As Phalcon is loosely coupled, you're free to use the full framework, or just specific parts of it as glue components. Rather than download an archive, extracting it to a directory like you do with most frameworks, Phalcon can be downloaded and installed as a PHP module. By creating a rich, fully featured framework written entirely in C and packaged as a PHP extension, Phalcon is able to save processor time and boost overall performance. While it is just under two years old, the Phalcon documentation, community and development rival that of many of the more mature frameworks available.

PHP-MVC - PHP-MVC is an extremely simple but effective Model-View-Controller application structure which is clean, easy to learn, highly documented and features a self-explaining structure and optional Composer integration. It comes in two versions, a basic and advanced, with the advanced version featuring additional Twig support and automatic SASS compiling in pure PHP. It is not a fully featured framework but instead provides a bare-bone structure, aiming to be extremely slimmed down. It's as simple and readable as possible, with a skeleton structure for quick application building, especially useful for those new to PHP. The project encourages coders to work according to PSR 1/2 coding guidelines, promoting the usage of PFO, and the use of external libraries via Composer. As it only uses native PHP code, there's no need to re-learn a framework, so you can get started straight away.

What are the differences between the echo and the print methods to get output?

1. Echo is slightly faster than print

2. Echo has no return value while print has a return value of "1" and can be used in expressions

3. Echo can take multiple parameters while print can only take one argument

Is multiple inheritance supported in PHP?

PHP supports only single inheritance; it means that a class can be extended from only one single class using the keyword 'extended'.

How can we display the output directly to the browser?

To be able to display the output directly to the browser, we have to use the special tags <?= and ?>.

What is the correct and the most two common way to start and finish a PHP block of code?

The two most common ways to start and finish a PHP script are:

<?php [ --- PHP code---- ] ?> and <? [--- PHP code ---] ?>

How to run the interactive PHP shell from the command line interface?

Just use the PHP CLI program with the option -a as follows:

php -a

What does PEAR stand for?

PEAR means "PHP Extension and Application Repository". It extends PHP and provides a higher level of programming for web developers.

What is the meaning of a final class and a final method?

'final' is introduced in PHP5. Final class means that this class cannot be extended and a final method cannot be overridden.

How is the comparison of objects done in PHP?

We use the operator '==' to test is two objects are instanced from the same class and have same attributes and equal values. We can test if two objects are referring to the same instance of the same class by the use of the identity operator '==='.

How can PHP and HTML interact?

It is possible to generate HTML through PHP scripts, and it is possible to pass pieces of information from HTML to PHP.

What type of operation is needed when passing values through a form or an URL?

If we would like to pass values through a form or an URL, then we need to encode and to decode them using htmlspecialchars() and urlencode().

How can PHP and Javascript interact?

PHP and Javascript cannot directly interact since PHP is a server side language and Javascript is a client-side language. However, we can exchange variables since PHP can generate Javascript code to be executed by the browser and it is possible to pass specific variables back to PHP via the URL.

What is needed to be able to use image function?

GD library is needed to execute image functions.

What is the use of the function 'imagetypes()'?

imagetypes() gives the image format and types supported by the current version of GD-PHP.

What are the functions to be used to get the image's properties (size, width, and height)?

The functions are getimagesize() for size, imagesx() for width and imagesy() for height.

How are failures in execution handled with include() and require() functions?

If the function require() cannot access the file then it ends with a fatal error. However, the include() function gives a warning, and the PHP script continues to execute.

What is the main difference between require() and require_once()?

require(), and require_once() perform the same task except that the second function checks if the PHP script is already included or not before executing it.

(same for include_once() and include())

How can I display text with a PHP script?

Two methods are possible:

<!--?php echo "Method 1"; print "Method 2"; ?-->

How can we display information of a variable and readable by a human with PHP?

To be able to display a human-readable result we use print_r().

How is it possible to set an infinite execution time for PHP script?

The set_time_limit(0) added at the beginning of a script sets to infinite the time of execution to not have the PHP error 'maximum execution time exceeded.' It is also possible to specify this in the php.ini file.

What does the PHP error 'Parse error in PHP - unexpected T_variable at line x' means?

This is a PHP syntax error expressing that a mistake at the line x stops parsing and executing the program.

What should we do to be able to export data into an Excel file?

The most common and used way is to get data into a format supported by Excel. For example, it is possible to write a .csv file, to choose for example comma as a separator between fields and then to open the file with Excel.

What is the function file_get_contents() useful for?

file_get_contents() lets reading a file and storing it in a string variable.

How can we connect to a MySQL database from a PHP script?

To be able to connect to a MySQL database, we must use mysqli_connect() function as follows:

mysql_pconnect() ensure a persistent connection to the database, it means that the connection does not close when the PHP script ends.

This function is not supported in PHP 7.0 and above

How is the result set of Mysql handled in PHP?

The result set can be handled using mysqli_fetch_array, mysqli_fetch_assoc, mysqli_fetch_object or mysqli_fetch_row.

How is it possible to know the number of rows returned in the result set?

The function mysqli_num_rows() returns the number of rows in a result set.

Which function gives us the number of affected entries by a query?

mysqli_affected_rows() return the number of entries affected by an SQL query.

What is the difference between mysqli_fetch_object() and mysqli_fetch_array()?

The mysqli_fetch_object() function collects the first single matching record where mysqli_fetch_array() collects all matching records from the table in an array.

How can we access the data sent through the URL with the GET method?

To access the data sent via the GET method, we use $_GET array like this:

www.url.com?var=value

$variable = $_GET["var"]; this will now contain 'value'

How can we access the data sent through the URL with the POST method?

To access the data sent this way, you use the $_POST array.

Imagine you have a form field called 'var' on the form when the user clicks submit to the post form, you can then access the value like this:

$_POST["var"];

How can we check whether the value of a given variable is a number?

It is possible to use the dedicated function, is_numeric() to check whether it is a number or not.

How can we check whether the value of a given variable is alphanumeric?

It is possible to use the dedicated function, ctype_alnum to check whether it is an alphanumeric value or not.

How do I check if a given variable is empty?

If we want to check whether a variable has a value or not, it is possible to use the empty() function.

What does the unlink() function do?

The unlink() function is dedicated for file system handling. It simply deletes the file given as entry.

What does the unset() function do?

The unset() function is dedicated for variable management. It will make a variable undefined.

How do I escape data before storing it in the database?

The addslashes function enables us to escape data before storage into the database.

How is it possible to remove escape characters from a string?

The stripslashes function enables us to remove the escape characters before apostrophes in a string.

How can we automatically escape incoming data?

We have to enable the Magic quotes entry in the configuration file of PHP.

What does the function get_magic_quotes_gpc() means?

The function get_magic_quotes_gpc() tells us whether the magic quotes is switched on or no.

Is it possible to remove the HTML tags from data?

The strip_tags() function enables us to clean a string from the HTML tags.

what is the static variable in function useful for?

A static variable is defined within a function only the first time, and its value can be modified during function calls as follows:<!--?php function testFunction() { static $testVariable = 1; echo $testVariable; $testVariable++; } testFunction(); //1 testFunction(); //2 testFunction(); //3 ?-->

How can we define a variable accessible in functions of a PHP script?

This feature is possible using the global keyword.

How is it possible to return a value from a function?

A function returns a value using the instruction 'return $value;'.

What is the most convenient hashing method to be used to hash passwords?

It is preferable to use crypt() which natively supports several hashing algorithms or the function hash() which supports more variants than crypt() rather than using the common hashing algorithms such as md5, sha1 or sha256 because they are conceived to be fast. Hence, hashing passwords with these algorithms can create vulnerability.

Which cryptographic extension provide generation and verification of digital signatures?

The PHP-OpenSSL extension provides several cryptographic operations including generation and verification of digital signatures.

How is a constant defined in a PHP script?

The define() directive lets us defining a constant as follows:define ("ACONSTANT", 123);

How can you pass a variable by reference?

To be able to pass a variable by reference, we use an ampersand in front of it, as follows $var1 = &$var2

Will a comparison of an integer 12 and a string "13" work in PHP?

"13" and 12 can be compared in PHP since it casts numbers to the integer type.

How is it possible to cast types in PHP?

The name of the output type has to be specified in parentheses before the variable which is to be cast as follows:

* (int), (integer) - cast to integer

* (bool), (boolean) - cast to boolean

* (float), (double), (real) - cast to float

* (string) - cast to string

* (array) - cast to array

* (object) - cast to object

When is a conditional statement ended with endif?

When the original if was followed by: and then the code block without braces.

How is the ternary conditional operator used in PHP?

It is composed of three expressions: a condition, and two operands describing what instruction should be performed when the specified condition is true or false as follows:Expression_1?Expression_2 : Expression_3;

What is the function func_num_args() used for?

The function func_num_args() is used to give the number of parameters passed into a function.

If the variable $var1 is set to 10 and the $var2 is set to the character var1, what's the value of $$var2?

$$var2 contains the value 10.

What does accessing a class via :: means?

:: is used to access static methods that do not require object initialization.

In PHP, objects are they passed by value or by reference?

In PHP, objects passed by value.

Are Parent constructors called implicitly inside a class constructor?

No, a parent constructor have to be called explicitly as follows:parent::constructor($value)

What's the difference between __sleep and __wakeup?

__sleep returns the array of all the variables that need to be saved, while __wakeup retrieves them.

What is faster?

1- Combining two variables as follows:
$variable1 = 'Hello ';

$variable2 = 'World';

$variable3 = $variable1.$variable2;

Or
2- $variable3 = "$variable1$variable2";

$variable3 will contain "Hello World". The first code is faster than the second code especially for large large sets of data.

What is the definition of a session?

A session is a logical object enabling us to preserve temporary data across multiple PHP pages.

How to initiate a session in PHP?

The use of the function session_start() lets us activating a session.

How can you propagate a session id?

You can propagate a session id via cookies or URL parameters.

What is the meaning of a Persistent Cookie?

A persistent cookie is permanently stored in a cookie file on the browser's computer. By default, cookies are temporary and are erased if we close the browser.

When do sessions end?

Sessions automatically end when the PHP script finishes executing but can be manually ended using the session_write_close().

What is the difference between session_unregister() and session_unset()?

The session_unregister() function unregister a global variable from the current session and the session_unset() function frees all session variables.

What does $GLOBALS do?

$GLOBALS is associative array including references to all variables which are currently defined in the global scope of the script.

What does $_SERVER do?

$_SERVER is an array including information created by the web server such as paths, headers, and script locations.

What does $_FILES do?

$_FILES is an associative array composed of items sent to the current script via the HTTP POST method.

What is the difference between $_FILES['userfile']['name'] and $_FILES['userfile']['tmp_name']?

$_FILES['userfile']['name'] represents the original name of the file on the client machine,

$_FILES['userfile']['tmp_name'] represents the temporary filename of the file stored on the server.

How can we retrieve the error when there is a problem with uploading a file?

$_FILES['userfile']['error'] contains the error code associated with the uploaded file.

How can we change the maximum size of the files to be uploaded?

We can change the maximum size of files to be uploaded by changing upload_max_filesize in php.ini.

What does $_ENV do?

$_ENV is an associative array of variables sent to the current PHP script via the environment method.

What does $_COOKIE do?

$_COOKIE is an associative array of variables sent to the current PHP script using the HTTP Cookies.

What does the scope of variables mean?

The scope of a variable is the context within which it is defined. For the most part, all PHP variables only have a single scope. This single scope spans included files and required files as well.

What's the difference between the 'BITWISE AND' operator and the 'LOGICAL AND' operator?

$a and $b: TRUE if both $a and $b are TRUE.

$a & $b: Bits that are set in both $a and $b are set.

What are the two main string operators?

The first is the concatenation operator ('.'), which returns the concatenation of its right and left arguments. The second is ('.='), which appends the argument on the right to the argument on the left.

What does the array operator '===' means?

$a === $b TRUE if $a and $b have the same key/value pairs in the same order and of the same types.

What is the differences between $a != $b and $a !== $b?

!= means inequality (TRUE if $a is not equal to $b) and !== means non-identity (TRUE if $a is not identical to $b).

How can we determine whether a PHP variable is an instantiated object of a certain class?

To be able to verify whether a PHP variable is an instantiated object of a certain class we use instanceof.

What is the goto statement useful for?

The goto statement can be placed to enable jumping inside the PHP program. The target is pointed by a label followed by a colon, and the instruction is specified as a goto statement followed by the desired target label.

What is the difference between Exception::getMessage and Exception:: getLine?

Exception::getMessage lets us getting the Exception message and Exception::getLine lets us getting the line in which the exception occurred.

What does the expression Exception::__toString do?

Exception::__toString gives the String representation of the exception.

How is it possible to parse a configuration file?

The function parse_ini_file() enables us to load in the ini file specified in filename and returns the settings in it in an associative array.

How can we determine whether a variable is set?

The boolean function isset determines if a variable is set and is not NULL.

What is the difference between the functions strstr() and stristr()?

The string function strstr(string allString, string occ) returns part of allString from the first occurrence of occ to the end of allString. This function is case-sensitive. stristr() is identical to strstr() except that it is case insensitive.

what is the difference between for and foreach?

for is expressed as follows:

for (expr1; expr2; expr3)

statement

The first expression is executed once at the beginning. In each iteration, expr2 is evaluated. If it is TRUE, the loop continues, and the statements inside for are executed. If it evaluates to FALSE, the execution of the loop ends. expr3 is tested at the end of each iteration.

However, foreach provides an easy way to iterate over arrays, and it is only used with arrays and objects.

Is it possible to submit a form with a dedicated button?

It is possible to use the document.form.submit() function to submit the form. For example: <input type=button value="SUBMIT" onClick="document.form.submit()">

What is the difference between ereg_replace() and eregi_replace()?

The function eregi_replace() is identical to the function ereg_replace() except that it ignores case distinction when matching alphabetic characters.

Is it possible to protect special characters in a query string?

Yes, we use the urlencode() function to be able to protect special characters.

How can we pass the variable through the navigation between the pages?

It is possible to pass the variables between the PHP pages using sessions, cookies or hidden form fields.

Is it possible to extend the execution time of a PHP script?

The use of the set_time_limit(int seconds) enables us to extend the execution time of a PHP script. The default limit is 30 seconds.

Is it possible to destroy a cookie?

Yes, it is possible by setting the cookie with a past expiration time.

What is the default session time in PHP?

The default session time in php is until the closing of the browser

Is it possible to use COM component in PHP?

Yes, it's possible to integrate (Distributed) Component Object Model components ((D)COM) in PHP scripts which is provided as a framework.

Explain whether it is possible to share a single instance of a Memcache between multiple PHP projects?

Yes, it is possible to share a single instance of Memcache between multiple projects. Memcache is a memory store space, and you can run memcache on one or more servers. You can also configure your client to speak to a particular set of instances. So, you can run two different Memcache processes on the same host and yet they are completely independent. Unless, if you have partitioned your data, then it becomes necessary to know from which instance to get the data from or to put into.

Explain how you can update Memcached when you make changes to PHP?

When PHP changes you can update Memcached by

Clearing the Cache proactively: Clearing the cache when an insert or update is made

Resetting the Cache: It is similar to the first method but rather than just deleting the keys and waiting for the next request for the data to refresh the cache, reset the values after the insert or update.